Hypsibema missouriensis
Encyclopedia
Hypsibema missouriensis is a species of plant-eating
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

 dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

 in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Hypsibema
Hypsibema
Hypsibema is a little-known genus of dinosaur from the Late Cretaceous . Its giant fossils were found in the U.S. states of North Carolina and Missouri...

, and the state dinosaur of the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...

. One of the few official state dinosaurs, bones of the species were discovered in 1942, at what later became known as the Chronister Dinosaur Site near Glen Allen, Missouri. The remains of Hypsibema missouriensis at the site, which marked the first known discovery of dinosaur remains in Missouri, are the only ones to have ever been found. Although first thought to be a sauropod, later study determined that it was a hadrosaur, or "duck-billed" dinosaur, whose snouts bear likeness to ducks' bills. Some of the species' bones found at the Chronister Dinosaur Site are housed in Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....

's Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...

.

Characteristics

The species is estimated to have had around 1,000 small teeth, weighed 3–4 ST (2.7–3.6 ) (or around as much as an elephant today), stood 10 feet (3 m) tall at its back, and stretched about 30–35 ft (9.1–10.7 m) from head to tail. Living in what is now southeast Missouri during the Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...

 age of the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 period, Hypsibema missouriensis is also one of the few dinosaur species to have exhibited strong maternal instincts, as they would stay close to their nests, although this is considered to be a general characteristic of hadrosaurs. While H. missouriensis was not a carnivorous
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

 species, its teeth were more serrated than other hadrosaurs, an indicator that the vegetation of Missouri at the time was very coarse or tough. From the size of the earliest recovered bones belonging to H. missouriensis, it is believed that the species had a long tail.

Paleontologist Charles Whitney Gilmore and geologist Dan R. Stewart described the caudal vertebrae retrieved from Missouri in a 1945 Journal of Paleontology
Journal of Paleontology
The Journal of Paleontology is a peer-reviewed scientific journal covering the field of paleontology, published by The Paleontological Society.-Indexing:The Journal of Paleontogy is indexed in:*BIOSIS Previews*Science Citation Index...

report, writing, "Caudal vertebrae amphicoelus; centra
Body of vertebra
The body is the largest part of a vertebra, and is more or less cylindrical in shape. For vertebrates other than humans, this structure is usually called a centrum....

 longer than wide; ends having concave central areas decorated with radiating ridges and depressions surrounded by a flattened peripheral border; chevron facets only on posterior ends." Of the thirteen adult tail bones, twelve appeared to be consecutive, and the smallest centrum was 69 millimetres (2.7 in) long.

Discovery

Remains of Hypsibema missouriensis were first discovered in Bollinger County, Missouri
Bollinger County, Missouri
Bollinger County is a county located in Southeast Missouri in the United States. As of the 2010 U.S. Census, the county's population was 12,363; despite a 2009 estimate that showed the population to be 11,841. The county seat is Marble Hill, which is the only city in Bollinger County...

 by members of the Chronister family while they were digging a cistern
Cistern
A cistern is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. Cisterns are distinguished from wells by their waterproof linings...

, and were subsequently collected by Stewart, later nicknamed "Dinosaur Dan." In 1942, Stewart, of the Missouri Geological Survey, had been examining clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 near Glen Allen when he came upon a boy who led him to the family at work digging. According to Stewart, property owner Lulu Chronister had found several "unusual" bones while digging and had saved them. They had been found about 8 feet (2.4 m) deep in the Chronisters' well, which had an overall depth of 24 feet (7.3 m), "imbedded in a black plastic clay." Stewart reported his discovery to the Smithsonian Institution, which bought the remains—thirteen vertebrae of a dinosaur's tail—from Chronister for US$50, which was later used to purchase a cow. Two other bones, of unknown type, were also recovered from the site, while one additional vertebrae had been given by Lulu Chronister to a friend. At the Smithsonian, the bones were analyzed but the species from which they originated was incorrectly identified.

The site where the bones were found was largely untouched by paleontologists until around 1990, when excavations restarted. Remains of other dinosaurs, fish, turtles, and plants have also been found, including teeth belonging to Tyrannosaurus rex. Other parts of H. missouriensis, including dental remains and part of a jaw, have also been found. The variety of fauna
Fauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...

l remnants found at the Chronister site suggest that a large body of water once existed close to the area.

Geology of dig site

Guy Darrough, a paleontologist from St. Louis, Missouri
St. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...

 currently working at the dig site, said it was "pretty much a miracle" that dinosaur bones were found in Missouri, because the state's soft soil has resulted in the deterioration of most prehistoric remains. However, some of the remains found have been damaged by erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 and other processes. While much of Missouri lies upon rocks from the Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...

 or Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...

 eras, the Chronister site is situated over Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

 rock. Stewart, who found the bones after being assigned to study the origins of clay in the southeastern portion of the Ozarks
The Ozarks
The Ozarks are a physiographic and geologic highland region of the central United States. It covers much of the southern half of Missouri and an extensive portion of northwestern and north central Arkansas...

, was able to conclude that part of the region lies upon deposits
Deposition (geology)
Deposition is the geological process by which material is added to a landform or land mass. Fluids such as wind and water, as well as sediment flowing via gravity, transport previously eroded sediment, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of...

 from the Upper Cretaceous period, although much of the sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

 from that time period has eroded away.

The Chronister family dug the well (which they ultimately abandoned after it was unable to provide enough water) just southwest of their farmhouse, atop a body of limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

. The farmhouse was located near the bottom of a steep valley, sitting atop the remains of a terrace. The layer of clay in which the bones were found was described by Stewart as being 9 feet (2.7 m) thick, situated below 7 feet (2.1 m) of yellow-brown clay and gravel at the surface, and above a dense mass of limestone.

The Chronister dig site is located atop the Ripley Formation
Ripley Formation
The Ripley Formation is a geological formation in North America found in the U.S. states of Alabama, Georgia, Mississippi, Missouri, and Tennessee. The lithology is quite consistent throughout the layer. It consists mainly of glauconitic sandstone. It was formed by sediments deposited during the...

. The land around the Chronister home and dig site sits atop sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 from the Lower Ordovician Period or Canadian Epoch
Canadian Epoch
The Canadian is the Lower or Early Ordovician in North America. The term is common in the older literature and has been well understood for more than a century...

. It is located in a section of the Ozarks affected by erosion and filled with chert
Chert
Chert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...

 and sandstone debris. In addition, the region has been impacted by frequent faulting, leading to the combination of rocks from different geologic periods. As a result, it is difficult to create an accurate geologic map
Geologic map
A geologic map or geological map is a special-purpose map made to show geological features. Rock units or geologic strata are shown by color or symbols to indicate where they are exposed at the surface...

 of the area.

Identification

Gilmore, at the Smithsonian, along with Stewart, first described the species as a sauropod in the January 1945 issue of the Journal of Paleontology, a classification made in error and without positive evidence. Gilmore only deemed the species a sauropod by process of elimination
Process of elimination
Process of elimination is a method to identify an entity of interest among several ones by excluding all other entities.-In education testing:...

; when he was left with the possibilities of Hadrosauridae and Sauropoda
Sauropoda
Sauropoda , or the sauropods , are an infraorder of saurischian dinosaurs. They had long necks, long tails, small heads , and thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land...

, he dismissed the former, saying, "The more elongate centra of the Chronister specimen, with the possible exception of Hypsibema crassicauda Cope, and the presence of chevron facets only on the posterior end appear sufficient to show that these vertebral centra do not pertain to a member of the Hadrosauridae."

The species, first called Neosaurus missouriensis, was renamed to Parrosaurus missouriensis later that year by Gilmore and Stewart because the name "Neosaurus" was preoccupied
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...

. However, Gilmore died soon after, and the bones were left untouched for several decades.

Parrosaurus missouriensis was once again moved in 1979, to the genus Hypsibema, this time by Donald Baird and John R. Horner. In the late 1970s, Bruce L. Stinchcomb, a geologist, traveled to the Chronister site after reading about Gilmore's report in the 1950s. He was able to purchase the property from a member of the Chronister family, and in the 1980s, test excavations were performed by Stinchcomb, David Parris, and Barbara Grandstaff, leading them to conclude that H. missouriensis was actually a hadrosaur rather than a sauropod. Thomas Holtz has suggested reverting to Parrosaurus for this species.

State dinosaur designation

On January 21, 2004, a bill was introduced in the Missouri House of Representatives
Missouri House of Representatives
The Missouri House of Representatives is the lower chamber of the Missouri General Assembly. It has 163 members, representing districts with an average size of 31,000 residents. House members are elected for two-year terms during general elections held in even-numbered years.In 1992 Missouri...

 by State Representatives Rod Jetton
Rod Jetton
Rod Jetton is a U.S. politician. He was a Republican member of the Missouri House of Representatives who has represented Missouri's 156th District from 2001 to 2009 and was Speaker of the Missouri House from 2005 to 2009.-Early life:Jetton was born in De Soto, Missouri, to Bill and Judy Jetton...

 and Jason Crowell. Jetton had originally proposed the hadrosaur as the state dinosaur, but was not specific enough, so the House Conservation and Natural Resources Committee settled on Hypsibema missouriensis. The bill was then sent to the 92nd Missouri General Assembly
Missouri General Assembly
The Missouri General Assembly is the state legislature of the U.S. state of Missouri. The bicameral General Assembly is composed of a 34-member Senate, and a 163-member House of Representatives. Members of both houses of the General Assembly are subject to term limits...

. It passed the Missouri House of Representatives
Missouri House of Representatives
The Missouri House of Representatives is the lower chamber of the Missouri General Assembly. It has 163 members, representing districts with an average size of 31,000 residents. House members are elected for two-year terms during general elections held in even-numbered years.In 1992 Missouri...

 on March 8, 2004 with a vote of 147–4, the Missouri Senate
Missouri Senate
The Missouri State Senate is the upper chamber of the Missouri General Assembly. It has 34 members, representing districts with an average population of 160,000...

 on May 14, 2004 with a vote of 34–0, and was approved by then-governor Bob Holden
Bob Holden
Robert Lee "Bob" Holden, Jr. is an American politician of the Democratic Party who served as the 53rd Governor of Missouri.-Early life:...

 on July 9, 2004. The bill, House Bill 1209, went into effect August 28, 2004. Missouri became the sixth U.S. state to have designated an official state dinosaur, following Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

, Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

, New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, and Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

, as well as the District of Columbia.

Local impact

In 2005, representatives from Bollinger County businesses and local government officials met in an effort to generate more revenue, and came up with a dinosaur-centered tourism campaign. Some businesses contributed to the creation of a billboard along Interstate 55
Interstate 55
Interstate 55 is an Interstate Highway in the central United States. Its odd number indicates that it is a north–south Interstate Highway. I-55 goes from LaPlace, Louisiana at Interstate 10 to Chicago at U.S. Route 41 , at McCormick Place. A common nickname for the highway is "double...

 that would advertise, "Bollinger County, Home of the Missouri Dinosaur." The Bollinger County Museum of Natural History, which displays some of the bones found, has said their exhibit on the species has attracted tourists from other parts of the United States, and the museum says the designation of H. missouriensis as the state dinosaur resulted in a tripling of visitors.

In March 2008, construction on a full-size model of a H. missouriensis was completed and placed on display at the museum. Jetton, then Speaker of the Missouri House of Representatives
Speaker of the Missouri House of Representatives
Speakers of the Missouri House of Representatives are :* 1820 James Caldwell * 1821 Henry S. Geyer * 1826 Alex Stuart * 1828 John Thornon * 1832 Thomas Reynolds * 1834 John Jameison...

, sponsored a dinner event for state legislators to celebrate the completion of the exhibit on March 7, 2008. The two-year project was directed by Darrough, who was also in charge of excavations at the Chronister excavation site, and is the only permanent museum exhibit to feature the species. At the opening of the exhibit, Jetton mentioned that he hoped the dig site would become part of a state park
State park
State parks are parks or other protected areas managed at the federated state level within those nations which use "state" as a political subdivision. State parks are typically established by a state to preserve a location on account of its natural beauty, historic interest, or recreational...

one day. Currently, excavation is being conducted by the Missouri Ozark Dinosaur Project. The site has been covered to prevent water from flowing over dig material. The Chronister dig site near Glen Allen, currently under private ownership by Stinchcomb, is the only location in Missouri where dinosaur bones have been found.

External links

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